CS 325: Software Engineering
February 5, 2015
Actor-System Interaction Modeling
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Foreground Processes
Expanded Use Cases
Foreground Processes
Actor-system interactions occur in the
foreground of a software system, where
the system interacts with the actors in
order to carry out the use cases.
Object interactions occur in the
background of a software
system, where internal objects
interact with each other in
order to carry out the use cases.
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February 5, 2015
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Foreground Processes
Consider the SIS use case model from Chapter 7.
Each of the use
cases in this model
involves interaction
between an actor
and the system.
Actor-system
interaction
modeling probes
deeper into the
specifications of
each use case.
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Expanded Use Cases
Consider the Academic Advisor’s “Check Prereqs” use case.
Actor: Academic Advisor
System: SIS
0. The system displays the main page.
1. TUCBW the academic advisor clicks the
Department Selection button from the main
menu.
2. The system displays the Department Name
listbox.
3. The academic advisor selects the department
from the Department Name listbox.
4. The system displays the Course Number
listbox.
5. The academic advisor selects the course from
the Course Number listbox.
6. The system displays the Course Information
page for the selected course.
7. The academic advisor clicks the Student
Selection button on the Course Information
page.
8. The system displays the Student ID textbox.
9. The academic advisor enters the student’s ID
number in the Student ID textbox.
10. The system compares the student’s
completed coursework in the database to
the specified course’s prerequisite list.,
identifying all missing prereqs.
11. TUCEW the academic advisor clicks the OK
button to clear the screen and return to the
main page.
TUCBW: The Use Case Begins With
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February 5, 2015
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TUCEW: The Use Case Ends With
Expanded Use Cases
Consider the Professor’s “Record Grades” use case.
Actor: Professor
System: SIS
0. The system displays the main page.
1. TUCBW the professor clicks the My Courses
button from the main menu.
2. The system displays the My Courses listbox.
3. The professor selects the course from the My
Courses listbox.
4. The system displays the Class Roster page,
containing a table of student names, ID
numbers, and grade drop-downs.
5. For each student in the Class Roster table, the
professor uses the grade drop-down to:
(a) Enter a letter grade, if possible.
(b) Enter a WP or WF, if possible.
(c) Skip the student, if W is the only entry.
6. For each entered grade, the system displays a
check mark in the Grade Entered checkbox.
7. The professor clicks the Finalize Grades button
on the Class Roster page.
8. The system replaces all grade drop-downs
with text labels.
9. TUCEW the professor clicks the Exit Roster
button to clear the screen and return to the
main page.
In step 5, notice how alternative flows are displayed.
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February 5, 2015
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In step 7, notice how exceptions (specifically, not entering
all grades in one session) are not displayed.